Copending application Ser. Nos. 503,146; 503,201, and 503,212, filed Sept. 4, 1974, now abandoned and incorporated into continuation-in-part applications 574,662, 574,829 and 574,664, respectively, filed May 5, 1975, which are assigned to the same assignee as the present application, disclose new and improved elevator systems in which the strategy utilized by the supervisory control is suitable for a microprocessor, such as Intel's MCS-4 and MCS-8, Rockwell's PPS, Signetic's PIP, National's GPC/P and AMI's 7300. These applications will be hereinafter referred to as the earlier filed copending applications. The microprocessor offers an attractive cost package as well as flexibility due to the LSI circuitry and programmability. While the microprocessor offers programming flexibility at a modest cost, it imposes certain restrictions due to its relatively limited speed and memory capacity. The copending applications set forth a universal operating strategy which accomodates all possible building configurations in which an elevator car may serve any combination of floors. The car controllers provide complete information to the system processor as to the building configuration which exists at any instant, and thus the supervisory control may be universally applied to any system without any significant modification. The strategy operates within the limited operating speed of a microprocessor because it does not decide when a hall call is registered which car should serve the call, and then output the assignment of the call to a specified car. Rather, it periodically assigns the up and down service directions of the floors to the cars by dividing the service directions among all in service elevator cars within the constraints of predetermined dynamic averages, which distributes the work load evenly among all of the elevator cars. While the strategy requires very little code to implement, enabling it to be accommodated by the limited memory capacity of a microprocessor, in most traffic situations it provides elevator service which equals or surpasses the more complicated strategies of the prior art in both average waiting time and longest waiting time.
Computer simulation of the new and improved universal strategy of the earlier filed copending applications, applied to hypothetical and known building configurations, using different traffic patterns, has pointed out a degradation in the quality of service during a peak traffic condition in one service direction, such as down peak. It would thus be desirable to raise the quality of service during traffic peaks to be consistent with the high quality service otherwise provided by the strategy. However, the improvement must be accomplished with minimal increase in instructions and code in order to remain within the memory capacity of a microprocessor.